In order to hear what's available, you'll need quality speakers or headphones... so like Bill said, just do some selective listening tests and see how you like it.

If you are concerned with it, return the card and get the Xonar DX. It's very similar to the D2 you have there, but costs half as much. It lacks the cool shield and lights, and also the killer bundle, but it does have the front panel header that you need.